Shoe sewing machine



March s, 1938. F. A. LARSON 2,11%50 SHOE SEWING MACHINE Filed Jan. 18, 1956 5 Sheets-Sheet l March 8, 1938. F. A. LARSON SHOE SEWING MACHINE 5 Sheets-Sheet 2 Filed Jan. 18, 1936 March 8, 1938. LARSON 2,110,650

SHOE SEWING MACHINE Filed Jan. l8, 1956 5 Sheets-Sheet 3 W l lum Q; 211m IIIIEI figrs n N O S R A L A F SHOE SEWING MACHINE Filed Jan. 18, 1956 5 Sheets-Sheet 4 arsn,

March 193. A LARSON 2,110,650

SHOE SEWING MACHINE Filed Jan. 18, 1936 5 Sheets-Sheet 5 Patented Mar. 8, 1938 2,1

UNITED STATES PATENT QFFIQE ,SHOE SEWING MACHHNE Frank A. Larson, Saugus, Mass.

Application January 18, 1936, Serial No. 59,723

20 Claims. (Cl. 112-8) This invention relates to sewing machines, and die, needle guide, aw], and loop-spreader momore particularly to lock stitch, curved hook neetion,

dle machines such as are commonly employed for Figure 6 is a plan view of the mechanism of securing the outsoles to boots and shoes. In Figure 5,

machines of this kind, owing to the fact that the Figure 7 is a sectional detail on line 7-1 of 5 several operative instrumentalities require to Figure 5, have variable quick and slow movements and Figure 8 is. a detail elevation of the needle,

dwells between movements, it has heretofore been needle guide and awl motion, showing the origin deemed necessary to employ numbers of cams of the motion from the main shaft,

or equivalent devices, and special gearing ar- Figure 9 is a detail elevation of the loop- 10 rangements, all of which have produced a large spreader motion, complement of friction and consumption of Figure 10 is a detail elevation of the shuttlepower and hence machines so constructedohave motion showing its origin from the main shaft required considerable power to operate them so of the machine,

that they are impracticable or diificult for man- Figure 11 is a detail elevation of the take-up i. ual operation as well as involving rapid wear of lever motion showing its origin from the main the parts and causing vibrations in the machine. shaft,

The prime object of the present invention is Figure 12 is a detail elevation showing the. to produce amachine of the kind stated wherein looper motion with its origin from the main substantially all of the requisite movements are shaft, 20 imparted to the usual or necessary instrumental- Figure 13 is a detail elevation showing the ities of such a machine by special and novel arloop-control arm, or loop-hook and the operating rangements of links and levers from a common means thereof,

rive shaft. In accordance with my invention, Figure 14 is a detail of the feeding mechanism '25 such system of links and levers are arranged showing its origin from the main shaft, and and adapted to produce all of the varied fast Figure 15 is a detail view looking in the direcand slow change movements and dwells of the tion of the arrows from the line |5i5 of Fig operative parts of the machine. By thus subme 14.

stantially eliminating friction producing tranS- All of the operative means to be described are mission such as cams and special gearing, I derived from a main shaft l journaled in the make the machine very much easier to operate base portion of a suitable machine framework and so that it can be readily operated by manual la. Such operative movements will now be sevpower if desired. The invention also compreerally described:

hends certain special improvements in the operative instrumentalities as will be later described. I" 'Looper and zoop'hook mono The foregoing and other objects and advan Referring particularly to Figures 12 and 13, tages of the invention will be better understood the looper and loop-hook motion is derived from from the following detailed description taken in the main shaft l through a crank arm 2 on the connection with the accompanying drawings, and main shaft 5 which oscillates a horizontal shaft 40 the distinctive features of novelty will be there a through a connecting li k 4 and upri ht arm 40 after pointed t i t appended claims, 5 which is pinned to shaft 3. Oscillating with Referring to the drawings: shaft 3 is a small upright arm 6. Pivoted to this Figure l is a side elevation of a machine emf is link 7 which operates thmugb three bodying my invention with parts broken away in links 8, 9 and ill to efifect oscillating motion in a section gear segment H, and to turn a gear l2 which is Figure 2 is a side elevation from the opposite fixed f i i 100p er 1 The i side of the machine to Figure 1, showing essenw t e s g n a .Such t at tial portions of the improved link and lever arme am shaft i from position shown- Figure 12, towards its oppos1te extreme position 59 langementsi for this motion, shown in dot and dash lines in Flgure 3 partial plan showmg the same figure, during the first part of such Gummy the lmkage arrangement of Figure 2, movement the looper remains without motion Figure 4 is a partial end V w 100king in the or an extremely small amount of motion, this direction 0f the arrows of u e being during a period of time in which the main Figure 5 is a detail elevation sh wing the neeshaft has rotated to a position shown in Figure 8 when the needle I4 is down through the work. Then while the main shaft I moves from its position shown in Figure 8 to the extreme position of Figure 12, a direct downward pull on the link it through links 1, 8 and 9 aifords a quick rotary motion to the looper l3 which casts the thread about the needle barb, according to usual practice. It will be understood that the described movement results because starting from the full line position shown in Figure 12, the downward movement of the link i to straighten the toggle links 8 and 9 operates through the link 9 upon the link ll] approximately at right angles thereto giving it very little movement, it being noted that the arm 5 is then in a position to impart least movement to the link 1. After the parts are moved downward past the straightened position of the links 8 and 9, the link 9 is then pulling downward relatively close to the turning axis of the link It causing the link it and hence the looper to receive a relatively much increased movement in the last part of the downward pull of the links I and 9. It is to be further noted that the degree of this differential movement is further accentuated by the relative arrangement of the arms 5 and 6 upon the shaft 3.

From the same connections, movement is taken to operate the loop-hook H: as seen in Figure 13. This loop-hook I5 is fulcrumed on the main frame in proper relation to the looper l3, as shown in Figure 2, and is operated by a bell crank arm it through a link H which is fulcrumed to the stud l8 which is a connecting stud for links 1, 8 and 9. The motion given to this loop-hook is a uniform motion. While the system of links and levers for actuating the active instrumentalities of my invention is of value and importance for operating elements such as the loop-hook l5 which has a relatively uniform motion, such system is of particular value for operating those instrumentalities which require -to have a quick operative movement with a slow movement or dwell between operating movements as above described for the looper. For the other operating elements to be now described, I employ linkage including toggle link systems generally simi lar to the link system I, 8 and 9 and which obtain the required movements without the use of friction creating gears and cams.

II.NeedZe motion The needle motion as best seen in Figure 8, is taken directly from the main shaft l by means of an extension of the crank arm 2 carrying stud l9 to which is pivoted needle lever 20, which operates the oscillating needle holder 2|, an awl carrier 21a, and the needle guide 22. The link 23 connecting the needle lever 20 affords the needle guide its proper timing. To adjust the needle guide position in relation to the needle barb, an eccentric or like means 22a may be applied to the connecting stud at one end of the link 23. The needle motion which is given to the needle holder H is transmitted to the awl carrier by a dowel pin Zlb fastened to the awl carrier Bid and working loosely in a hole in the needle holder or clamp 2|. This allows the awl carrier to move laterally for feeding the work while being turned by the dowel pin 2 lb. As later more fully explained, provision is made for changing the rate of such work feeding movement of the awl carrier while the machine is in operation and the needle holder in movement.

II I .--Loop-spreader motion As best seen in Figure 9, the loop-spreader motion is taken from the needle clamp arm through a link 2 pivoted thereto at one end and having its other end pivoted to a pair of toggle links 25, 25. When the main shaft rotates to a. position shown in dot and dash lines in Figure 8, the needle clamp arm is brought to a position shown in dot and dash lines in Figures 8 and 9 which in turn draws the toggle links 25, 2E downward, rotating shaft 28 by means of the universal link 2'! secured to said shaft. Being fastened to shaft 28 the loop-spreader 29 receives an upward swing shown in dot and dash lines in Figure 9 at the same time that the shaft 28 receives its rotating motion. It will be noted that the arrangement of links 24, 25 and 26 is similar to that of links I, 8, 9 of the looper motion, and affords to the loop-spreader a quick motion after a dwell, similar to that given to the looper.

IV.Shuttle motion As best seen in Figure 10, pivoted to the stud I53 which, as stated is carried by an extension of crank arm 2, is a link 30 attaching to a crank arm 3! pinned to a shaft 32 journalled in the machine frame. Owing to the link connection from one crank to the other, the motion given to shaft 32 is an uneven fast and slow motion alternating during each revolution. From this motion is taken the shuttle motion shown in Figure and to produce such motion with the proper timing a crank arm 33 is pinned to the shaft 32. On this crank arm 33 a link 34 extending angularly thereto is pinned to stud 35 carried by the crank arm 33, and an oscillating motion is transmitted to a shaft 36 fulcrumed in the main frame by a connecting link 31 from the link 35 to the crank arm 38 fixed on a shaft 36. The necessary oscillating shuttle motion is taken from the crank arm 38 by a connecting link 39 through a gear segment and gear 40, 4| and a bell crank arm 42 and thence to the shuttle housing 43.

V.-Thread tension control As best seen in Figure 2, a positive thread tension control arm 64 has an arm 45 extending obtusely rearward therefrom, these two arms being in one and constituting a bell crank lever fulcrumed to the machine frame. From the arm 45 a link 46 extends to a short crank arm 41 pinned to the oscillating shaft 36 which constitutes a part of the shuttle motion as described.

The arm 44 carries at its extremity a small roller .8 over which the thread T passes, the motion which this roller receives being such, that while the usual thread tension spring may be employed, the thread is kept taut at all times without being placed under a breaking strain, without the aid of the'ordinary tension spring. In regard to this motion it will be noted that at the time the toggle arrangement 'l-8-9 operates on link IE, moving loop-hook l5 rearward carrying with it the thread T, the arm 44 moves downward giving to the loop-hook the necessary amount of thread, and continues to move downward as the looper l3 casts the thread about the needle barb thereby giving to the looper its proper length of thread. At this point the loop spreader 29 takes the thread to cast it about the shuttle while the take up arm M (to be presently described) gives the necessary amount of thread, and while the take-up returns to its downward position taking-up the surplus thread in making the stitch, the positive-thread tension control arm 44 also returns to its normal upward position. The action of the two levers it and M working in opposite directions at the crucial moment when the stitch is being made insures a good tight stitch. Cooperating with this mechanism an automatic thread measuring device (to be presently described) aids in obtaining a tight and even stitch.

VI .-Feedz'ng motion As best seen in Figure i l, the feeding motion is also controlled by the shaft 35. Pinned to this shaft is a link 59. A connecting link 5t from link 59 to arm 5! which is pinned to a stud 52 fulcrumed in the machine frame, gives an oscillating motion to the cam 53 which is also pinned to the stud 52. A forked lever 5t fulcrumed in an adjustable housing 55 receives a rocking motion which is transmitted as an oscillating motion to shaft 5t through universal connecting links M, 53. Pinned to the shaft 53 is a forked link 59 which straddles a pin 5Q projecting from a hollow shaft 6| giving it a reciprocating motion which is thus given to an adjustable pin 62 held in hollow shaft 6! by suitable clamping means as seen at 653. Fastened to this pin 62, is a yoke 64 which straddles the awl carrier 2la giving to it the described reciprocating motion for feeding the work, it being understood that the present machine is of that type wherein the work .is fed by a lateral movement of the awl while engaged through the Work. To obtain an adjustment for aligning the awl with the needle, the yoke 64 is secured to the pin 62 by a shouldered screw 65 allowing the pin 62 to be turned. This pin carries a threaded portion that screws into the hollow shaft Bl, which has an internally threaded portion for this purpose, and by turning the pin 62 by its knurled head 65, the awl can be moved laterally for the necessary adjustment. The feeding cam 53 is so located on stud 52 that the proper dwell and feeding motion is obtained with the assistance of the linkage 49, 50 and 5E. The arrangement of these links is also similar to that of the links l, 8, 9 of the lo-oper motion, and affords a quick feeding motion. The amount of feed is governed by changing the fulcrum point of the forked lever 54 by moving the housing 55 which carries this fulcrumed point along the horizontal shaft Bl carried in the machine frame, by use of the handle 68, as seen in Figure 1, which is fulcrumed to the frame at 59, and connected to housing 55 by link iii. It is thus possible to change the amount of feed, i. e., the spacing of the stitches while the machine is in operation by operating the handle 68.

VII.- -Take-up motion As best seen in Figure 11, the take-up motion is derived from the stud 35 on the crank arm 33 pinned t6 the shaft 32 which is s' pplied with an uneven and alternating fast and slow motion as previously described. Pivoted at one end to this stud 35 a link ll connects to a bell crank it fulcrumed on the shaft A connecting link 13 connects the arm l'Za of this bell crank to the take-up lever it which is fulcrumed to the machine frame at T5. The lever i bears at its extremity a small roller l fe around which the thread T passes from the tension roller 4-8 to the shuttle and needle mechanism.

VIIl.Presser foot mechanism As best seen at Figure 2, the presser foot mechanism derives its movement from the stud it which is the connecting stud for the take-up bell crank 72 and its connecting link H. The motion of this bell crank is transferred to an-. other bell crank ll fulcrumed to the machine frame at it, by a connecting link 79. Attached to the bell crank H is a link 89 carrying a cam roll ill, which cam roll is also connected to, and under the control of, a link I05 to be later further described. This cam roll operates in a cam slot in a lever 82 which is fulcrumed to the machine frame at 33. Attached to this lever $12 by stud 8d is a block 85 adapted to slide in a frame or housing 86. This frame 86 is attached to a presser foot lever 8i fulcrumed on the machine frame at I38. Two locking pins 39, 90 held in wedge shaped grooves in the slide block 85 by fiat springs Hi, 92, lock the slide block 35 in its frame 8E causing the frame and block to move as one unit. After the cam lever 82 has been forced downward by the action of the cam roll 8| in the cam slot, thus raising the presser foot 93, the flat faces of the cam lever 82 shown at M, come to such an angle as to act against the rollers 96, 91 borne by the ends of locking pins 89, 98, causing the locking pins to release the slide block 85, this constituting a self-dis-- connecting device which then allows the spring 98 to act on the presser foot lever 81 through lever 99, fulcrumed at 9911 and engaging the presser foot lever at 9919; thus moving the presser foot down to operative position. The presser foot can also be operated manually by handles it'll, Elli. Handle liil effects the release of locking pins 39, 98 through the toggle links if, "it connected thereto by link Hi l, which links are connected at one end to the machine frame and at their other end to the rocking lever Hi5 whiclr through a link I96 is connected to the cam roller 8!. The handle loll which is fastened to the presser foot lever may be used to lift the presser foot.

IX.-Automatic thread measuring device As best seen in Figures 1 and 2, a mechanism is employed to automatically measure and take from the spool the amount of thread to be used in making each stitch. As the amount of thread, necessary, varies with the thickness of the material which is being stitched, the device is controlled by the presser foot 93 which bears on the work, continually acting as a caliper. Pinned to the extremity of shaft Sii-a is an arm I01 with a projecting pin E88. Fulcrumed in the machine frame at it, an arm H0 is held against the pin E68 by spring Hi fastened to the frame. In the underside of arm lit; a screw H2, which may be felt capped, is in position to be contacted by the bell crank arm 72a of hell crank 12 in its upward travel. A spring H3 is fastened to arm lie. The thread comes from the spool and is temporarily gripped between the pin H18 and underside of arm Hi3; it then passes through a hole in arm it? for controlling purposes and thence up and under spring H3 where it is permanently, gently gripped by spring H3 bearing down on it. Thence it continues to the wax pot, up over the positive-thread-tension control arm roller 38, thence to the take-up arm roller Ida,

and on to the looper l3. As the bell crank arm 52a travels in its upward motion, it strikes against the screw H2, which may be adjusted in or out, raising arm ill} from its resting position on pin it. As thread is being gripped at this point, it will be noted that as the arm H is raised, the thread is immediately released, and being permanently gripped by spring l3 attached to arm Me, an amount of thread is drawn from the spool which is governed only by the amount of lift that is transmitted to arm HQ. As the bell crank arm E20, moves to its downward position returning arm lid to its gripping position on pin I83, the amount of thread drawn from the spool rests in loop form on the forward side of pin i118, ready to be used for the coming stitch. As the presser foot is raised or lowered, it will be noted that shaft 98a is oscillated which in turn raises or lowers the contacting pin Hi8 thereby governing or determining the amount of lift which is to be given to arm Hi? and consequently controlling the amount of thread necessary for the stitch in the thickness of work on which the presser foot rests. It will be noted that at the time the arm 54 and arm 14 are working against each other to draw the stitch tight, that the action of the thread on arm iill is such that it is pulling it downward on pin H38 thereby tending to grip the thread harder, the tighter the stitch is being drawn.

Certain other features of, or accessories to, a complete lock stitch sewing machine such as a heated wax pot for coating the thread, are not herein shown or described since they form no part of the present invention and have no novel cooperative relation with the features shown and claimed herein.

I am aware that the invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and I therefore desire the present embodiment to be considered in all respects as illustrative and not restrictive, reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

Having nowdescribed my invention, what I claim as new and desire to secure by Letters Patent is:

1. A look stitch sewing machine comprising awl and needle mechanism, shuttle mechanism, work feeding mechanism, a prime drive shaft with connections to all of said mechanisms to operate the same, and a looper equipped with rotating means, said rotating means having a direct link and lever connection to the prime drive shaft embodying a plurality of cooperative toggle devices, one working through another and arranged to impart very quick operative movements to the looper rotating means with relatively long dwells between such movements.

2. A look stitch sewing machine comprising a prime drive shaft having connections to operate all the operative instrumentalities of the machine, embracing a looper equipped with rotating means, said rotating means directly connected from the prime drive shaft by a crank on such shaft, a link from such crank, a bell crank connected to such link, a second link and a toggle device con nected to the second link and to the looper rotating means arranged to impart to th looper quick operative movements with dwells between such movements.

3. A look stitch sewing machine as described in claim 1 having a loop hook with a link connection to the toggle device to be operated in connection therewith.

i. A look stitch sewing machine'comprising a prime drive shaft, a work feed, and awl and needle mechanism including an oscillating needle holder, connected to be operated from such drive shaft, such connection to the needle holder embodying a crank on the prime drive shaft, an arm extending from the needle holder and a direct link connection from said crank to said arm.

5. A look stitch sewing machine as described in claim 4 having an oscillating needle guide with a link connection to an extension of the link which operates the needle holder arranged to impart a differential movement to the needle guide with respect to that of the needle holder.

6. A look stitch sewing machine comprising awl and needle mechanism, work holding and work feeding mechanism, a single drive shaft connected to operate all of said parts and having a direct link and lever arm connection to the needle holder to oscillate the same, and a loop spreader having a linkage connection to the needle holder embodying a toggle link device arranged to impart quick operating movements to the loop spreader with intervening dwells.

7. A look stitch sewing machine as described in claim 6 wherein the loop spreader is mounted to turn about an axis at an angle to the axis of the needle holder with a universal joint connection thereto from said toggle link device.

8. A look stitch sewing machine comprising awl and needle mechanism, a work feed, an oscillating shuttle, a single drive shaft for all of said parts, and a link and lever system directly connected with both said shaft and said shuttle to turn the shuttle, arran ed to impart quick operative movements to the shuttle with a dwell between such movements.

9. A look stitch sewing machine as described in claim 8 wherein the connections from the prime drive shaft to the shuttle embrace a second shaft mounted in offset parallel relation to the prime drive shaft with a link and lever arm connection from one to the other arranged to impart an irregular alternating fast and slow movement to the second shaft, and with a link and lever connection from said second shaft to the shuttle adapted to accentuate such irregular motion to impart to the shuttle quick operative movements with a dwell therebetween.

10. A look stitch sewing machine as described in claim 8 wherein the connections from the prime drive shaft to the shuttle embrace a second shaft mounted in parallel offset relation with respect to the prime drive shaft with a longer crank on the prime drive shaft connecting through a link with a shorter crank on the second shaft to impart irregular alternating fast and slow movements to the second shaft, and a link and lever arm connection from the second shaft to the shuttle arranged and adapted to increase the extent of such irregularity of movement to impart quick operative movements to the shuttle with dwells between such movements.

11. In a lock stitch sewing machine a single prime drive shaft connected to actuate all the operating instrmnentalities of the machine, a shuttle, and a toggle link system of connections from said shaft to the shuttle arranged to operate the same with quick operating movements and a dwell between such movements.

12. In a lock stitch sewing machine having awl and needle, shuttle, and work feed mechanisms, a prime drive shaft for operating all said mechanisms, connections from said shaft to the shuttle including a toggle link system and a shaft 36 for imparting quick operative movements to the shuttle with a dwell between such movements, and a thread tension control device embracing a bell crank lever having a link and lever arm connection to said shaft 36 to be actuated thereby.

13. A look stitch sewing machine comprising a prime drive shaft, awl and needle mechanism with the awl borne in an awl carrier, shuttle mechanism, and work feed mechanism, embracing a linkage system including a toggle device from the prime drive shaft to the awl carrier arranged to impart quick operative movements to the awl carrier with dwells between such movements.

14. A machine as described in claim 13 wherein the connections from the prime drive shaft to the awl carrier include also a lever mounted to turn on a fulcrum, said fulcrum having adjustment endwise of. said lever for varying the rate of feed at will while the machine is in operation.

15. In a lock stitch sewing machine a prime drive shaft, a shuttle, a linkage system for turning the shuttle from said prime drive shaft constructed and arranged to impart quick operative movements with a dwell between such movements to the shuttle, said linkage system embracing an oscillating shaft 36, an awl carrier, and means for reciprocating said awl carrier from the shaft 36 embracing a toggle device adapted to impart quick operative movements to the awl carrier with dwells between such movements and embracing also a lever having a fulcrum adapted for adjustment while the machine is in operation to vary the rate of feed.

16. A look stitch sewing machine comprising a prime drive shaft, awl and needle, shuttle, and work feed mechanisms connected thereto, such connection to the shuttle including a second shaft mounted in parallel ofiset relation to the prime drive shaft with means for turning it with an irregular fast and slow movement with respect to the prime drive shaft, and a thread take-up device comprising a bell crank lever having link and lever connections to operate it from said second shaft, said link and lever connections arranged and constructed to partake of the fast and slow movements of said second shaft to impart quick operating movements to said take-up device with dwells between such movements.

, 17. In a lock stitch sewing machine a prime drive shaft, a thread take-up device, and a linkage system direct from said prime drive shaft to said take-up device embracing a plurality of cooperative toggle devices arranged in series with one working through another constructed and arranged to transmit and transform uniform movements of the prime drive shaft as quick operating movements of the take-up device with dwells between such movements.

18. A look stitch sewing machine comprising a prime drive shaft, feed mechanism, awl and needle mechanism, and shuttle mechanism connected through toggle link connections to be actuated therefrom with quick operating movements and dwells between such movements, and a presser foot connected to partake of such quick operating movements with a self-disconnecting device interposed in such connection arranged to come into operation as the presser foot is lifted to a pre-determined degree, with spring means for thereafter depressing the presser foot to operative position.

19. An apparatus as set forth in claim 18 equipped with manual means for lifting the presser foot and with cooperative manual means for rendering said disconnecting device operative.

20. A look stitch sewing machine comprising a prime drive shaft, shuttle mechanism, awl and needle mechanism, and feed mechanism with connections from the prime drive shaft to each of the said mechanisms, each of. said connections embodying a linkage system including a toggle device adapted to impart quick operating movement to its operated element with a dwell between such movements.

FRANK A. LARSON. 

